In the current state of technology, it is established practice for aircraft cabins to be divided up into different sections or zones. The cabin temperature can be regulated in the individual zones. In order to heat the aircraft cabin, ventilation air taken from a mixing chamber is mixed with hot engine bleed air and then blown into the zone of the cabin in question. Regulation of the cabin temperature is controlled by means of a central cabin temperature regulator. For this, a pre-specified nominal cabin temperature is compared with the actual value shown by a cabin temperature sensor. A control deviation of the cabin temperature results from the difference between the nominal and the actual value. A nominal value for the input air temperature in the cabin is determined by the characteristics of the cabin and the control deviation. This nominal value for the input air temperature is compared with the value measured by a temperature sensor in the input air supply line. A further control deviation for the input air temperature is given by the difference. This control deviation is leveled out by the controlled mixing of hot bleed air by means of a mixer valve.
The known solution is based upon simple heating up of the air supplied to the sections of the cabin, ie. the input air, by mixing in the engine bleed air. This has the following disadvantages:                A mixer valve must be installed for each cabin zone.        A bleed air line to the mixer valve must be installed for each cabin zone. For safety reasons, the installation of a hot air leakage monitoring unit is also associated with this.        For reasons relating to weight, the metal bleed air supply lines must be as short as possible and the mixer valves must therefore be installed near to the wing box. The result of this is that there is a long input air line to each cabin zone with the corresponding weight, and the cost of integrating this input air line into the aircraft.        For each of the mixer valves used, a control outlet on the cabin temperature regulator is required. The number of cabin zones in which the temperature can be regulated is therefore limited to the maximum number of available control outlets.        